Method of making lap pin

ABSTRACT

A method for forming a lap pin is disclosed, the lap pin being used with a cotton picker in one of the first stages of the processing of cotton from its baled condition into yarn. A lap pin is employed in the machine in order to roll up the first portion of the processed cotton into a lap. The lap pin is a single piece of forged steel having its end turned down to final dimensions for positioning within the picker. The sharp corners at the two ends are provided to accurately size the unit but the unit itself is completely of one piece construction to eliminate breakage at joints or securing points of a multi-piece lap pin, and the material is selected of high carbon steel to provide a spring action to accommodate foreign material which is always found present in the cotton as it passes through the picker. The method consists of a two-step forging which results in uniform molecular flow around the joint between the ends and the body portion. In addition, heat treating in a carburizing atmosphere at a temperature of not less than 1,450*F. for not less than four hours is set forth.

United States Patent [191 Anthony Mar .4, 1975 METHOD OF MAKING LAP PIN William Edward Anthony, Lynwood Rd, Gastonia, NC. 28052 22 Filed: Jan. 28, 1974 21 Appl. No.: 436,872

Related US. Application Data [62] Division of Ser. No. 188,193, Oct. 12, 1971, Pat. No.

[76] Inventor:

Primary Examiner-Lowell A. Larson Attorney, Agent, or Firm-Dominik, Knechtel, Godula & Demeur [57] ABSTRACT A method for forming a lap pin is disclosed, the lap pin being used with a cotton picker in one of the first stages of the processing of cotton from its baled condition into yarn. A lap pin is employed in the machine in order to roll up the first portion of the processed cotton into a lap. The lap pin is a single piece of forged steel having its end turned down to final dimensions for positioning within the picker. The sharp corners at the two ends are provided to accurately size the unit but the unit itself is completely of one piece construction to eliminate breakage at joints or securing points of a multi-piece lap pin, and the material is selected of high carbon steel to provide a spring action to accommodate foreign material which is always found present in the cotton as it passes through the picker.

The method consists of a two-step forging which results in uniform molecular flow around the joint between the ends and the body portion. In addition, heat treating in a carburizing atmosphere at a temperature of not less than 1,450F. for not less than four hours is set forth.

3 Claims, 5 Drawing Figures METHOD OF MAKING LAP PIN CROSS REFERENCE TO RELATED APPLICATION This application is a division of parent application Ser. No. 188,193, filed on Oct. 12, 1971, in the name of William Edward Anthony and entitled: LAP PIN AND METHOD OF MAKING SAME," now US. Pat. No. 3,807,649.

DESCRIPTION OF INVENTION The present invention relates to a method of forming a one piece forged lap pin. The lap pin is used in a cotton picker machine for building up a lap prior to the replacement of the lap pin within the lap and processing while supported on a lap pin. Such devices are used conventionally in a machine such as a Whitin picker.

BACKGROUND OF INVENTION In the processing of cotton, the same is removed from the hale and then worked through a picker machine of the character set forth in Whitin catalogs made by the Whitin Machine Works of Whitinville, Mass, USA. FIG. 1 of the present patent application shows such a machine. The lap pin is at the output end of the machine, and the lap of cotton is rolled up on the pin. A typical lap will be 38 to 40 inches in length, approximately 12 to l4-inches in diameter and weigh between 50 and 60 lbs.

As the lap is rolled up on the pin, the pin is subjected at both ends to tremendous downward pressuresin order to pressure and roll the lap tightly. While visual inspection is intended to remove foreign matter from the cotton bales as presented into the picker, it is not uncommon for foreign matters as large as a railroad spike to pass through the machine. With the conven tional lap pin, such as shown inFIG. of the drawings, these pressures will tend to break the joints where the roller is attached to the shaft by means of collars, sleeves, and the like. Sometimes the same will separate. This causes down time in addition to an expensive repair.

OBJECT OF THE INVENTION The principal object of the method of the present invention is to provide a method for forming the lap pin which will result in smooth molecular flow and orientation ofthe steel at the joint defining the body of the rollers.

DESCRIPTION OF DRAWINGS Further objects and advantages of the present invention will become apparent as the following description of an illustrative embodiment proceeds, taken in con- FIG. 5 is a longitudinal sectional view taken from approximately the same position as that of FIG. 4 illustrative of the prior art type of lap pin.

DESCRIPTION OF PREFERRED EMBODIMENT For an understanding of the problems of breakage with a lap pin of the prior art, as well as how these problems are overcome by a lap pin illustrative of the present invention, reference can be made to the Whitin picker machine shown in FIG. 1. Such machines cost many tens of thousands of dollars, and process the baled cotton 2 from one end, through the various rollers and processing elements of the Whitin machine 1 until the same comes out in a fluffy band of cotton at the lap rollers 4, the opposite end of the Whitin machine 1 wherein the bale of cotton has been loaded.

While one does not like to criticize suppliers or other tradesmen, often enough so that repeated problems may be encountered, unscrupulous cotton merchants may drop metal refuse and the like in the cotton bales 2 in order to increase the weight of the bale and obtain the price for a lesser quantity of cotton. Many times such items, in actual fact as large as a railroad spike, will pass all the way through a Whitin picker machine 1 until the time that the cotton is being wrapped up into a lap of cotton 3 on the lap rollers 4. Referring now to FIG. 2, it will be seen that pressure jaws 5 are positioned adjacent the lap rollers 4 at a mid position thereof, and are lowered with extreme force and pressure so that the pressure jaw roller 6 engages the lap pin 10, and the lap pin 10 is permitted to roll in the lap pin crotch 7 of the pressure jaws 5.

Even though the cotton lap 3 as illustrated on a lap pin 10 in FIG. 3 appears like a large fluffy tube, it is in fact tightly rolled by the pressure jaws 4, and accordingly does not afford much give" when foreign material passes over the lap rollers 4. When such foreign material passes by, the immense and continuing pressure of the pressure jaws 5 will cause the ends of a conventional lap pin 10 to shear at the point where (see FIG. 5) the body 11 is joined to the end tubes 12 by means of the spacer collar 14. This can occur by actual shear (along the general lines of the broken portion shown on the right hand side of FIG. 5) or by the separation of the spacer collar 14 from the body 11. In either event, when such breakage does occur it is possible that loose parts will fall down between the lap rollers 4 and do additional damage to the Whitin machine 1. Furthermore, once the lap pin 10 has broken, if it is not fully lapped, that portion of the cotton is lost. The time to replace the lap pin, and indeed to repair damaged lap rollers 4, is a major expense. In today's market (1971) the cost of a conventional prior art lap pin such as illustrated in FIG. 5 is approximately $50.00. The cost of a breakdown, however, can be easily 10 times that much when translated in machine down time, lost processing of cotton, and damage to adjacent equipment in the Whitin picker 1 or other comparable machine.

The solution to the problem presented by the breakage of the prior art lap pins is to form a lap pin 20, illustrative of the present invention, as shown in FIG. 4, from a single forging. Not only is the employment of a single forging important, but all steps of the forging process should be conducted to the end that the final lap pin 20 has the maximized characteristics of good spring steel. To achieve this end, a steel tube is originally selected for forging from a high carbon steel. The same may be either hot or cold formed to swage the ends 22 which engage the pressure jaws 5 and lap rollers 4 of the picker 1. After forming, the lap pin 20 is then carburized in accordance with those techniques best calculated to impart the maximum spring-like action to the lap pin 20.

Subsequently to forming, the shoulders 24 are finished by conventional machining operations as is the outside diameter of the end tube jaw engaging members 22.

Particularly to be noted, as set forth illustrative in FIG. 4, is the smooth flow of the molecular orientation 25 at the joint between the roller body 21, the shoulder 24, and the end tube engaging members 22. By ready comparison between FIG. 4 illustrating the lap pin 20 ofthe present invention, and FIG. 5 immediately therebeneath illustrating the prior art type lap pin 10, it will be observed that critical weak areas appear at the joint between the shoulder 15, the spacer collar 14, and the end tube engaging rollers 12. All of these critical elements are minimized by the provision of a one-piece forging, and more particularly by carburizing the high carbon steel from which it is forged to the end that the stresses generated by foreign material passing beneath the body rollers 21 are distributed throughout the length of the lap pin 20, and not concentrated at the joints ofthe separate elements from which the prior art type lap pin is fabricated.

Further to be observed in FIG. 4, is that one of the body rollers has a narrow hole in its central portion, whereas the other has a large hole. The end with the larger hole will commonly be provided with a lap stick (not shown) which engages its interior portion. The lap stick engaging bore 26, it will be observed, presents a radius collar 28 in the interior portion of the body roller 21. This configuration does not necessarily imply additional strength, nor detract from the same. The result flows primarily from the sequential swaging action in which the larger lap stick engaging bore 26 is provided.

THE METHOD In a typical commercial operation, the high carbon steel employed is designated commercially as A grade. Once the piece is cut to length, it is then subjected to the following swaging and forging or forming steps:

1. Both ends of the tubular piece are then heated to forging temperature depending upon the type of steel used, the preferable method of heating being by induction coils.

2. The tube is then placed in a first die which swages the ends partially down to size but leaving a distinct hollow bore interiorly of the two swaged ends.

3. The ends are again heated to forging temperature by induction coils and the final die is applied to swage the ends to the correct dimension.

5 4. In one embodiment of the design, one end is swaged completely to be closed, the swaged closed end (after carburizing) being machined to form a handle. Single step swaging or forging has been attempted, but the metal appears to develop flaws from the extent of the forming which occurs in reducing the same to finished size in one operation. On the other hand, by engaging in the two-step forming as set forth above, a smooth flow of the molecular orientation of the steel at the joint of the body and the ends results.

After the above steps have been completed, carburizing is accomplished by treating in a gas oven at a temperature of not less than l,450F. for a period of not less than four hours in an atmosphere characterized by 0.24 percent carbon content. After the same is removed, it is either oil quenched or air cooled. Thereafter the machining is done to the ends as set forth above.

Although particular embodiments of the invention have been shown and described in full here, there is no intention to thereby limit the invention to the details of such embodiments. On the contrary, and intention is to cover all modifications, alternatives, embodiments, usages housing equivalents of a lap pin as fall within the spirit and scope of the invention, specifications and the appended claims.

What is claimed is:

1. A method of forming a lap pin, comprising the following steps,

cutting a piece of high carbon tubular steel to preferred length,

heating both ends to forging temperature,

swaging both ends partially down to size, but retaining a hollow bore in the thus partially sized ends, reheating the partially swaged ends to forging temperature,

thereafter swaging the ends to correct dimensions,

and heat treating the resultant in a carburizing atmosphere.

2. In the method of forming a lap pin set forth in claim 1 above,

heat treating the same in a carburizing atmosphere of approximately 0.24 percent carbon at a temperature of not less than l,450F. for a period of not less than four hours.

3. In the method of claim 1 above,

swaging one end in the second swaging step to complete closure, and after heat treating, forming the 

1. A METHOD OF FORMING A LAP PIN, COMPRISING THE FOLLOWING STEPS, CUTTING A PIECE OF HIGH CARBON TUBULAR STEEL PREFERRED LENGHT, HEATING BOTH ENDS TO FORGING TEMPERATURE, SWAGING BOTH ENDS PARTIALLY DOWN TO SIZE, BUT RETAINING A HOLLOW BORE IN THE THUS PARTIALLY SIZED ENDS, REHEATING THE PARTIALLY SWAGED ENDS TO FORGING TEMPERATURE THEREAFTER SWAGING THE ENDS TO FORGING TEMPERATURE, AND HEAT TREATING THE RESULTANT IN A CARBURIZING ATMOSPHERE
 2. In the method of forming a lap pin set forth in claim 1 above, heat treating the same in a carburizing atmosphere of approximately 0.24 percent carbon at a temperature of not less than 1,450*F. for a period of not less than four hours.
 3. In the method of claim 1 above, swaging one end in the second swaging step to complete closure, and after heat treating, forming the same into a handle. 